i have a circuit with three ICs (so far), with output from one serving as input to the other and so on. the first is a PIC which passes a logical HIGH or LOW to an OR gate, and finally to a D-flip-flop. the problem is that the HIGH output from the PIC is about 3.8V. this is acceptable to TTL but the output from the OR gate is less than 2V.

<image here>

does any1 have an idea of how to make all the outputs from each IC to be only either 5V or 0V (HIGH or LOW)?
i once used a voltage regulator to accomplish a similar goal but i was having voltages that were higher than 5V volts. the voltage regulator made them five volts. right now i am thinking of using a BJT like PN2222 to accomplish that but i want to know if there is another way, an easier way.
unless the problem is from how i connect to my IC inputs and outputs (i use pull-down resitors), this should be a problem faced everyday by others.

This is not very clear. What are the IC's that you are using? What is the Vcc applied to them? Is it the same as the Vcc to the PIC? Why pull-down resistors? If you have a limited output switg with TTL it is possible to use pull-up resistors to improve the situation (a pull-down is tied to circuit ground, a pull-up is tied to Vcc).

the ICs i am using are PIC16F877A, 74LS32, and 74LS273. i am not using a pull up resistor, will that help? but i am using pull down resistors. all the ICs have the same VCC, the problem is that the outputs from each IC, which should be equal to VCC or ground, are less than VCC. the output decreases with more ICs.
pls refer to the image i attached to the first thread.

beenthere: i am using the pulldown resistors because the outputs were not stable when i was not using them earlier. now i'll try doing without them again.

Audioguru n Sgtwookie: yes, those voltage levels are approximately wut i get. my problem is after gettin 3.8V from an output as logical HIGH, i get 2.0V as output from the next whose input was the 3.8V previously mentioned. i am looking for a way to make that 3.8 to 5V before passing to the next IC. now i'll also try using pull up resistor.

Bill: i'll take ur advice but since i have most of the components to try the suggestions by beenthere, audioguru n Sgtwookie, i'll make it a last step.

Normally, you dont need pull down resistors. if your outputs are astable is due to noise or bad connections. If your pull down resistors have a low value, then the output of the chip will source a higher amount of current than with a higher value resistor. This higher value of current causes a significant voltage drop across the internal resistance of the IC and causes the output voltage to be lower than expected.

ok Guys, now the problem is solved. i have all the outputs giving me a value of about 4V.
the problem origniated from the PIC, the 74LS32 and 74LS273 were just passing on the error originating from the PIC like a chain reaction.
what i did was i inserted a pull-down resistor at the PIC's output, this made the voltage level increase from about 3.8V to 4.2V. i removed all the pull-down resistors at the outputs of 74LS32, this made the voltage to increase from about 3V to 4V. 74LS273 was no different and the final output was about 4V.
i guess the moral here is diff ICs have diff requirements... . thnx